It's All in the Diagnosis
I own a BMW 325i 1995. It's an automatic car I purchased from an elderly lady in mint condition. She never really drove it on the highway (only city driving). Lately, my front wheels shudder if I reach a speed of 120 km or 75 mph. I believe it is the tie rods. When I go over slight curbs or bumps it makes a knocking sound, especially when I go up the ramp of my parkade. I haven't taken it to the shop yet as it drives normally in the city on smoother surfaces. Could it be anything else?
Mac
via the Internet
It is impossible to say for sure without having the car for diagnosis, but I can tell you that the overwhelming majority of BMW steering wheel vibrations are caused by simple wheel balancing problems. Bent wheels will certainly do it as well, and sometimes worn out front control arm bushings will lead to a shake. I don't know if your tie rods are worn, but I seriously doubt they are causing the vibration. Time now to bring the car to a professional BMW technician for road testing and diagnosis.
Need a Clutch
I have just purchased a 1988 320is. I love the car, but it needs a clutch. I have found little information on the car other than only around 4,000 of them were made between 1987 and 1991, and they were only sold in Italy and Portugal. It is identical to the 1988 320i in terms of the body, however it has a 2-liter S14 Motorsport engine and the same gearbox as the M3. Will the clutch be the same as the M3 for that year?
Petty Officer Second Class George Lock
United States Navy
Sicily, Italy
Nice find, AO2 Lock. The Italian-specification 320is was a factory homologation so that the 2.0-liter version of the M3's S14 engine could be used in European Touring Car racing. Yes, it uses the same 228mm clutch as the E30 M3. The BMW clutch kit part number is 21 21 2 226 854. The clutch kit includes a clutch disc, pressure plate, and release bearing. Be advised that other parts may be worn in there as well, such as the clutch release fork, release fork pivot, and release fork spring. If the kit contains the new style plastic release bearing, no lubrication is required. If the release bearing has a metallic housing, lubricate the input shaft housing with high-temperature anti-seize compound mixed with a few drops of engine oil. Always lubricate the input shaft splines all contact points of the release fork, pivot, and spring. Also, dot the pressure plate fingers with this anti-seize compound and motor oil mixture. This will give you a happy clutch.
Wheel Quandary
My questions are regarding wheels, in particular the ideal wheels for my recently purchased 1996 328i. I understand that 17 inches is an ideal size for all around aggressive street driving, but I was wondering what an ideal width would be, and also what an ideal tire size would result in a stock diameter. Also, I've been debating with my WRX friend the importance of manufacturing processes and weights. Obviously forged is ideal, but I'm looking at spending about $200 per wheel. I'm wondering how much weight should be considered, and will I notice a difference in street performance between a 16 lb. wheel and a 21 lb. wheel?
Nik
via the Internet
First off, understand that if you are running the stock suspension you will want to at least upgrade your shock absorbers before going to larger wheels and tires. I recommend Bilstein HD shocks if you are going to keep the stock coil springs and Bilstein Sport shocks if you're going to install shorter, firmer, aftermarket coil springs. You'll also want to replace the rear shock mounts and gaskets.
Check out the new Meyle design rear shock mounts from Bavarian Autosport (www.bavauto.com). You should also verify the condition of the rear trailing arm bushings and replace them if necessary with E46 M3 units. Bear in mind these bushings must be loosened while installing new rear springs, and then torqued with the suspension in normal operating position, not full droop, otherwise they will be preloaded and will fail quickly. Also if you lower the car, I recommend E30 M3 aluminum front control arms and E30 M3 offset front control arm bushings. Finally, if the car is lowered, align it to E36 M3 specifications.
Now on to your wheel question. Your correct upgraded tire sizes are 225/50-16, 225/45-17, or 235/40-17. You are good to go with the first two assuming the correct wheel offset, but I cannot promise you that 235/40-17s will fit without clearing the rear quarter panels. For wheel size, 7x16, 7.5x17, or 8x17 in. will be ideal with these tire sizes, repectively. Personally, I'd go with 7x16-in. wheels and 225/50-16 tires, just for economy's sake and a wider choice of less expensive, high-end tires. For an excellent discussion of the affect of wheel weight upon performance and ride, visit this link at Tire Rack's Web site: http://www.tirerack.com/wheels/tech/road_wheel_weights.htmlMany wheel weights are listed here:
http://www.superhonda.com/tech/wheel_weights.html
Wheel weight information is not always readily available when we discuss wheels in print--or even when you buy wheels. But your question is a good one; it's a savvy enthusiast who wonders about wheel weight. I'll never forget BMW Car Club of America's Gateway Tech 1993 in St. Louis, when BMW of North America sent two technical representatives to discuss, among other things, the upcoming GPS navigation system. The leader said, "This guy here can answer any question you might have about the new BMW GPS Nav system..." One guy in the back of the room raised his and and said, "How much does it weigh?" If you've never seen a German engineer squirm in front of his boss, it's worth just about any price.
Aiming High
I am wondering if I can put an S54 M3 motor into an E30 3 Series. I know E36 engines can bolt up to the stock E30 gearboxes, and E36 cars carry over engines into the E46. I have a complete wrecked M3 with the SMG transmission to use for parts. I personally do not want the SMG because a computer controls the clutch--personal taste, no arguments please. I know it would be wiser and make more sense to put the S54 into an E36, but I blew all my money on the M3 so all I can afford is an E30. Imagine the potential of a 2,800-lb car with 333 hp.
What will I have to do to perform the conversion? Will I need to custom fabricate mounting locations for the engine? Is the engine ECU a stand-alone system where all I need to do is swap the E46 ECU and all the interior lights, etc., will be working? The differential is still in working order on the M3, so can I swap with the E30 unit? Do I need a custom driveshaft? What kind of performance do you think I can expect? So far, suspension-wise I'm thinking PSS9 coilovers, but I have seen some nice TW racing coilovers for a lot less. I can weld, so chassis strengthening will be up on the list alongside making sure this car stays true to its European roots.
My original plans were to stick an M70 into an E36, but the E36 is gone and I feel there is more potential with the E30 due to its lighter weight. Last but not least, I don't want a big wing on the car but I can't imagine how much lift would occur at speed, especially with this much power. The E30 M3 piano spoiler is already a little much, but increasing the angle (60 degrees max) should perform as good if not better if the wing were as wide, wouldn't it? I intend this car to be a sleeper with the capability of winning bets with NSXs and leaving some non-skilled Ferrari drivers in awe at the track.
Oh, by the way, is there anything wrong with doing a brake stand where the speedo is showing 160 yet the car is stationary other then melting rubber? My friends are doing it a lil' often...
Anonymous
via the Internet
What you propose is certainly possible, but an enormous project. Initially, I would recommend you contact www.zionsvilleautosport.com with respect to the engine conversion, because they have already installed several S50/S52 engines in the E30 3 Series. Some fabrication will be required in terms of engine fitment and the exhaust system. There is no way to make an S54 not an OBD-II engine, so you'll most likely have to live with an eternal "check engine" light.
You won't get any arguments here regarding your decision against the SMG, godforsaken infernal contraption that it is. You can use an E30 Getrag 240 five-speed overdrive gearbox (you don't say which E30 you have there), which I believe will bolt to the S54, but Zionsville will know for sure. There's no telling how long this unit will hold up behind an S54, but it's pretty beefy and if you run good synthetic gearbox oil like Red Line MTL it'll probably be OK depending upon service demands. If you use the E30 gearbox then you can keep the driveshaft and the differential. Whether that differential is going to have the ratio you want depends upon the E30 you have, which we don't know. Forget about using the E46 differential; that won't work.
You'll also need the biggest E30 radiator you can install, which would be a 325i radiator. I'd say PSS9s would be a good choice if you want adjustability, but you could save money by simply installing Bilstein Sports and H&R coil springs for a 325i. Make sure you use E30 M3 offset front control arm bushings, and if you buy larger anti-roll bars, I'd recommend every reinforcement sold by Turner Motorsport (www.turnermotorsport.com).
Rear axle lift is clearly an issue on the E30 3 Series, but only above about 110 mph or so. So, if you're building this car to drag race or "sit and spin" like your brake-stand friends, then rear axle lift won't be an issue for you. But if you're gonna pull heavy Rs with the big boys, you're going to need a rear spoiler or wing, no question. Forget about the way it looks and get one that works. The M3 unit is a good choice, but depending upon how fast you want to drive, the BMW M-Technic rear spoiler would work, too, if you can find one. This unit resembles the E28 535is/M5 rear spoiler, and is larger than the 318is/325is rear spoiler, but it's no longer available from BMW last time I checked.I think you can expect performance that will flatten your eyeballs, and the trick will be not flattening the car and yourself in the process. Bear in mind the E46 has a far more advanced suspension than even a performance-modified E30. And there's only so much tire you can fit in the wheel housings of an E30. I know that 215/40-17 or 225/50-15 are the most you'll get under there, and these are the correct sizes for speedometer/odometer integrity.
Last, in my opinion, "brake stands" serve absolutely no purpose other than to wear out drivetrain components and tires, get you beat up or killed by testosterone-enraged onlookers, or arrested by testosterone-enraged police officers.
Stroker Searching
I'm searching for a stroker kit for my 1991 318is. It has 170,000 miles on it. I was wondering if there are any kits that offer high compression plus a bump in displacement, maybe 2.0-liters or more. Here in Pennsylvania there is no emissions testing so I'm OK on that part.
Eric Sierra
Bushkill, PA
The German tuner Hartge once had a 2.1-liter stroker kit for the M42 engine, but today their scientific name is "unobtanius familiarus." They are long gone. You already have pretty high compression at 10.5:1. If your M42 is like most of them, the bottom end is fine even at 170,000 miles, but you need a timing chain, oil pump, and valve job, or at least new lifters, valve guides, and valve guide seals. If you can stomach the expense of a valve job and a set of Schrick cams, that combined with a chip, intake, and exhaust system will yield about 165-170 hp, which is about all you're going to get out of an M42. And it still won't have much low-end torque. Keep the stock cams and do the rest, and you'll wind up with about 150 hp or so. If it's acceleration you're after, your best best is a 4.27 limited-slip differential from a 1991 318i convertible. This is a bolt-in modification, and it won't affect the speedometer/odometer reading due to BMW's electronic speedometer pickup.
Surging Idle Problem:Usually the Idle Control Valve
I did an engine conversion on my 1993 318i sedan with a five-speed manual gearbox. I installed an M50 engine and wiring harness out of a 1992 325i into the car last month. Everything went very smoothly except one thing. It idles at approximately 1,700 to 2,000 rpm and constantly surges. From time to time it will surge up to about 4,000 rpm and stay there until I turn the key off and reset it.I took it into the car doctor and they diagnosed it as having a bad throttle position sensor; the diagnostic machine said that the digital motor electronics had no signal in the idle position from the throttle position sensor. I went home and took the throttle position sensor off my 318i engine (which has the same sensor) and I still have the same symptom. I took a volt/ohm meter and tested the three wires going to the throttle position switch. One wire was a common ground, one read constant 5 volts, one wire read 0 volts in the closed position and moved to 4 volts as I turned the throttle to the full position. I think the fault lies somewhere in the throttle position sensor circuit. This is very frustrating.
Tracy Hahn
Monroe, OR
The throttle position switch test specifications are set forth in the Bentley E36 3 Series Service Manual, which you need to buy if you are going to be working on this car. With the harness connector disconnected and the ignition switch on, terminals 3 and ground should have 5 volts. With the harness connector disconnected and the ignition off, terminals 1 and 3 should have 4k ohms resistance. With the throttle plate rotated from idle to full open throttle position, terminals 1 and 2 at the sensor should vary between 1 and 4k ohms without interruption.
However, I can tell you that 95% of surging or fluctuating idle problems on BMWs result from a faulty idle control valve, not the throttle position sensor.